Sawhead vertical adjusting friction winch and self-locking/braking system for sawmill

Abstract

A friction winch and braking system for a sawmill having a cutting mechanism for sawing lumber. The friction winch and braking system allows for easy, one-handed raising and lowering of the sawmill head within the sawmill carriage and the automatic braking of the sawhead at the vertical plane chosen by the operator.

1. A sawmill carriage for use on a sawmill base and with a saw head, comprising:
 a horizontal base having an assembly which provides planar horizontal movement when fitted onto a set of rails of a sawmill base; 
 a vertical saw support having a horizontal base and extending vertically therefrom; 
 a cross rail attached to a first vertical saw support; 
 whereby the vertical saw support and the cross rail form a rigid frame; 
 a rotate rod extending horizontally from said vertical saw support, said rotate rod being capable of axial rotation; 
 at least one lift cable configured to raise or lower the saw head when said rotate rod is rotated; and 
 a friction winch/brake assembly capable of frictionally imparting an adjustable resistance to the axial rotation of the rotate rod; 
 said saw head being slidably affixed to said rigid frame and affixed to the lift cable such that rotation of the rotate rod displaces the saw head in a generally vertical direction. 
 
     
     
       2. The sawmill carriage of  claim 1 , further comprising a saw rod support which houses the rotate rod. 
     
     
       3. The sawmill carriage of  claim 2 , wherein the lift cable comprises a first cable end and a second cable end, wherein said lift cable is configured to wrap or unwrap around the rotate rod when said rotate rod is rotated. 
     
     
       4. The sawmill carriage of  claim 3 , further comprising a pulley system through which the lift cable is fed for converting displacement of the cable into a generally vertical direction. 
     
     
       5. The sawmill carriage of  claim 4 , wherein the pulley system is affixed to the vertical saw support. 
     
     
       6. The sawmill carriage of  claim 4 , wherein the pulley system is affixed to the cross rail. 
     
     
       7. The sawmill carriage of  claim 1 , wherein adjustable resistance to the axial rotation of the rotate rod is directionally biased such that greater resistance is provided to clockwise axial rotation than to counterclockwise axial rotation, or vice versa. 
     
     
       8. The sawmill carriage of  claim 2 , wherein the friction winch/brake assembly comprises:
 a friction winch cable affixed at a proximal end to a fixed anchor point located on the saw rod support, and affixed at a distal end to an adjustable anchor point also located on the saw rod support; 
 a screw capable of displacing said adjustable anchor point and thus adjusting tension in said lift cable; 
 wherein the friction winch cable is wrapped at least once around said rotate rod. 
 
     
     
       9. The sawmill carriage of  claim 8 , wherein the friction winch cable is wrapped at least twice around said rotate rod. 
     
     
       10. The sawmill carriage of  claim 8 , wherein the adjustable anchor point is a floating anchor point and the screw comprises a handwheel biased by a spring such that tightening said handwheel compresses said spring and displaces said floating anchor point toward said handwheel. 
     
     
       11. The sawmill carriage of  claim 8 , further comprising a drum having at least two collars, affixed to and rotationally engaging said rotate rod, wherein the friction winch cable is wrapped around said drum and between said two collars. 
     
     
       12. The sawmill carriage of  claim 1 , wherein said vertical saw support comprises a first vertical saw support and a second vertical saw support, and said cross rail and said rotate rod extend from said first vertical saw support to said second vertical saw support. 
     
     
       13. The sawmill carriage of  claim 1 , further comprising a crank having a crank handle operatively connected to the rotate rod and capable of rotating the rotate rod axially when rotated. 
     
     
       14. The sawmill carriage of  claim 1 , wherein vertical displacement of said saw head relative to said carriage is configured to be controlled with only one hand of an operator. 
     
     
       15. The sawmill carriage of  claim 1 , wherein said friction winch/brake assembly provides automatic braking of said saw head at a vertical plane chosen by an operator. 
     
     
       16. A sawmill comprising:
 a sawmill base having a set of rails and support for said rails; 
 the sawmill carriage of  claim 1 , positioned on said sawmill base such that the sawmill carriage is capable of running along the rails and providing planar horizontal movement of the sawmill base; 
 a saw head slidably affixed to the vertical saw support such that rotation of said rotate rod raises or lowers said saw head.